Known linear embroidery machines make it possible to produce a wide variety of patterns. By means of the repeat color pattern changing automatic systems they can couple and decouple embroidery stations in any required manner especially in order to embroider colored patterns. The disadvantages of the known linear embroidery machines, however, are that their technical equipment is extraordinarily elaborate so that the costs associated with the latter and the space requirements cannot be satisfied in many instances, and that the performance of these machines is relatively limited with respect to the output as well as with respect to production of new designs.
A mono embroidery machine of the abovementioned kind is already known U.S. Pat. No. 3,680,545, in which the embroidery tools associated with an embroidery station are arranged so that they can be adjusted, by means of a drive shaft which covers the whole vertical height of the embroidery field, in the vertical and horizontal directions and which are pushed in an enclosed housing or in an embroidery head above each other on a drive shaft which passes through the housing or through the embroidery head and which can be adjusted in any required manner steplessly in the height for the purpose of varying the repeat depending on the embroidered pattern. Individual or mono embroidery heads are pushed on the drive shaft for this purpose. The disadvantages of this arrangement are that a needle interval, which has once been set between vertically superposed needles, remains fixed, the embroidery work which is being produced can be observed only poorly or not at all, no means are available for reaching by hand to the embroidery fabric and long changeover times are necessary which are associated with a high production loss. Moreover, it is not possible to use these mono embroidery heads as means for creating patterns or to use these heads as means for forming of embroidery patterns in relation to each other within an overall embroidery field.
A double or duo embroidery head of a drive shaft group to eliminate these disadvantages and to simplify and make cheaper the drive of the embroidery heads has already been proposed: this arrangement considerably increases the pattern creating possibilities by staggering the embroidery heads of a double embroidery head in the vertical and horizontal direction and by decoupling of some embroidery heads. However, neither the mono nor the duo embroidery heads separately make it possible to obtain simultaneously a staggered as well as linear arrangement of embroidery heads and the technical total outlay for separate components is relatively high; moreover, the coefficient of friction on the deflecting positions is very high, the space requirement for application of embroidery heads of this kind is also relatively high so that, in order to restrict the claim on space, the fitting of the head must be very compactly carried out and this does not make possible observation and access to the embroidery fabric. Furthermore, the mounting possibilities of mono as well as duo heads are unfavorable because the head must be pushed over the shaft; for this reason an undesirable height increase also occurs. A further decisive disadvantage of the mono or duo embroidery heads is the very severely restricted scope in varying the patterns, either in a staggered or linear manner. Finally, the manufacturing and fitting costs for embroidery machines with such mono or duo heads are also very high.
Since needles and piercers in the embroidery process do not carry out their functions simultaneously and they are effective successively after each other in the embroidery process, it therefore appears feasible to drive needles and piercers by a common drive if it is possible to design this drive in such a manner that the needles and piercers can be actuated in a staggered order in time and hence the needle and piercer movements can be carried out separately in time. Furthermore, the yarn cutting arrangement does not function when embroidering or piercing is carried out and, alternatively, the needle and piercer are out of action when the yard cutting arrangement is effective, so that the three functions, i.e. embroidering, piercing, yarn cutting are never carried out simultaneously but always successively in time, one after the other.
In piercing drives, which were known previously or proposed, all piercers have carried out the same working process so that the piercing effects could be used only to a very limited extent for pattern making. A piercer hole is made when a conical mandrel cuts the fabric open for a certain penetration depth into the embroidery base fabric and this establishes the diameter of the pierced hole. Embroidering is then carried out around the pierced hole. Decoupling or actuation of each individual piercer independently from another, in the conventional embroidery machines as well as in the embroidery machines already proposed by the applicant, is not intended and it is not possible.
The basic object of the invention is to create an embroidery machine which avoids the disadvantages of surface embroidery machines with single or double heads as well as the disadvantages of known linear embroidery machines, but which, however, combines the advantages of both systems. Hence the object of the present invention is an embroidery machine, especially a surface embroidery machine with universal embroidery heads, by means of which the automatically controlled embroidery stations can be coupled and decoupled individually, in groups, or all together depending on the requirements of the pattern and in which the technological effort for this purpose is intended to be kept relatively low.
A further object of the present invention is to develop universal embroidery heads of this kind in such a manner that they can be supplemented in modular form for further special working processes and in which additional components can be mounted on the given universal embroidery head. This should make it possible for the surface embroidery machine, which has been known for some time and which at present is still a special machine, to be used as an all round machine whose pattern range can be significantly extended also in comparison with that of the linear embroidery machine. It is a further object of the invention to create an embroidery machine, especially a surface embroidery machine, in which the needle piercer drive means are combined so that only one common drive is needed for both features. Moreover, the design will also include an arrangement so that the piercers can be coupled and decoupled individually or in groups in one or several basic guides or at all embroidery stations of the machine in any required manner in order to achieve in this way a wider range of patterns by extending the piercing effects.